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Introduction

Use the After Effects expression elements along with standard JavaScript elements to write your expressions. You can use the Expression Language menu at any time to insert methods and attributes into an expression, and you can use the pick whip at any time to insert properties.

  • For resources on how to get started with expressions, see Resources.
  • For some broad examples, see Examples.
  • For info on changes to the expression engine over the years, see Changelog.

Within each page, you'll see categories for each logical group of pages, and then specific pages within each category.

When you open a page, you'll be presented with:

  • A brief introduction to that topic ("This is what the page is about")
  • Headers for Attributes and Methods
  • Attributes are accessible bits of information:
    • thisComp.name gets the name of the comp!
    • text.sourceText.fontSize gets the font size of the text
  • Methods are functions that you run, to either get some other info or generate a result:
    • thisComp.layer("Banana") retrieves a layer called Banana, or
    • text.sourceText.setFontSize(123) will set the font size to 123

  • A list of each expression method or attribute alphabetically sorted under its header, which includes:

    • The name of the item
    • At least one way of how to access it from an expression (ie if you want to use the "TextStyle.font" item, you access it via text.sourceText.style.font)
    • A brief description on what the item does & how it works

    • The type of info an attribute provides, or the type of info a method returns(1)

      1. Some return-value descriptions include a number in square brackets—this number specifies the dimension of the returned property or Array.

        If a specific dimension is not included, the dimension of the returned Array depends on the dimension of the input.

    • (Methods only) A list of all arguments/parameters needed to call the method, including optional arguments/parameters(1)

      1. If an argument description contains an equal sign (=) and a value (such as t=time or width=.2), then the argument uses the included default value if you don't specify a different value.

        Some argument descriptions include a number in square brackets—this number indicates the dimension of the expected property or Array.

    • And, sometimes, an example showing how to use that item

Tip

The docs also include notes (where applicable) indicating any other warnings, bugs, issues, or tips that may apply to a given item. We've also tried to provide info on when an item was added into After Effects, so that you can ensure it'll work for your project.

A Note on Sources

Please note that the majority of this document is community-supported and community-generated by volunteers just trying to help out!

While we're lucky enough to have some Adobe staff keeping these docs up-to-date with each version of After Effects, their time and energy is also being donated in a volunteer capacity.

If you have any questions, comments, or concerns about anything in these docs – or if you'd like to contribute (no code experience necessary!), propose suggestions, or anything else – please reach out to the admins at hi@docsforadobe.dev.